The goal is to ensure quality for a period of time after you buy it. That can be several days to several weeks, depending on the item. For instance, milk, assuming proper refrigeration, should last five to seven days past its sell-by date before turning sour.
An autoencoder is a neural network that is trained in an unsupervised fashion. The goal of an autoencoder is to find a more compact representation of the data by learning an encoder, which transforms the data to their corresponding compact representation, and a decoder, which reconstructs the original data.
Transducers (such as optical or magnetic encoders) sense position or orientation for use as a reference or active feedback to control position: 1  A rotary encoder converts rotary position to an analog (e.g., analog quadrature) or digital (e.g., digital quadrature, 32-bit parallel, or USB) electronic signal. A linear encoder similarly converts linear position to an electronic signal. Such encoders can be either absolute or incremental. The signal from an absolute encoder gives an unambiguous position within the travel range without requiring knowledge of any previous position.